The present invention relates to a speed reducer with gears having parallel axes.
The possibility of eliminating clearance between the sides of the teeth of two meshing gears with parallel axes by providing the related sets of teeth with a slight taper is known. Said gears are mounted so that their tapers are directed toward opposite sides and are moved axially toward one another until the teeth make contact on both the homologous side and the antihomologous side.
However, the problem of eliminating clearances between the sides of the teeth in gears of multiple-stage speed reducers has not been solved. This problem currently occurs in several applications, in particular for robotics.
Internal clearances not only increase the noise of the reducer, but also produce a transmission error, i.e. an angular offset of the output shaft. In this respect, reducers which limit transmission error to a maximum of 3 minutes of a degree are generally considered to be of the low-clearance type.